Earcup assemblies for attenuating ambient sound in noisy environments, such as in or around military helicopters or other aircraft, are known in the art. Such assemblies are shown, for example, in U.S. Pat. Nos. 3,190,973, 3,470,564, 3,875,592 and 3,943,572, issued to applicant Jackson A. Aileo and owned by the assignee herein. As shown in the first patent identified above, the earcups of such assemblies may house earphones to allow communication or monitoring of the ambient sound. Generally in such assemblies the earcup shells, which comprise a rigid plastic, are about a quarter-inch thick to provide the necessary sound attenuation. As will be apparent from the above description, not only are such assemblies heavy, and thus uncomfortable after extended use, but the rigid plastic shell transmits lateral impact forces, such as might be sustained if the wearer falls against a hard object, almost without attenuation.